bool SerialConnVT::Key(dword key, int)
{
    bool processed = false;
    // split key and flags.
	dword flags = K_CTRL | K_ALT | K_SHIFT;
    dword d_key = key & ~(flags | K_KEYUP); // key with delta
    flags = key & flags;
    //
	if (d_key & K_DELTA) { // can't capture RETURN
	    if (key & K_KEYUP) {
	        processed = ProcessKeyUp(d_key, flags);
	    } else {
	        processed = ProcessKeyDown(d_key, flags);
	    }
	} else {
	    if (key < 0xffff) {
	        processed = ProcessChar(d_key);
	        ProcessKeyDown(d_key, flags);
	    } else if (key & K_KEYUP) {
	        // RETURN will reach here
	        ProcessKeyUp(d_key, flags);
	    }
	}
	if (processed) {
	    mScrollToEnd = true;
	}
	return processed;
}

Thanks very much. I've read the VT102's mannual, it taked me lot of time. ECMA48, Xterm, oh, no!